function getRandom(min,max) {
    return Math.floor(Math.random()* (max -min +1) + min);
}
var random = getRandom(1,10);
while (true) {
    var num = prompt('请输入一个1~10的整数：');
    if (num === null) {
        break;
    }
    else if (num > random){
        alert('你猜大了');
    }else if (num < random){
        alert('你猜小了');
    }else {
        alert('恭喜你，猜对了');
        break;
    }
}